In recent years, a liquid-crystal display apparatus has been utilized as a display apparatus of a TV receiver or a personal computer. Because a liquid-crystal display apparatus such as this can be formed in a thin shape, whereby it is space-saving, and is power-saving, it has widely been utilized. However, a liquid-crystal display apparatus such as this has a problem in that response time between input of image data and actual display is long. In this regard, as a drive method to improve the response speed of a liquid-crystal display apparatus, it has been proposed that image data to be displayed is compared with the immediate previous image data and over-voltage driving with raised voltage is implemented in accordance with the result of the comparison (refer to Japanese Patent Laid-Open No. 11-126050).
FIG. 17 is a graph for explaining an example of the over-voltage driving signal; the ordinate denotes the voltage applied to a liquid crystal, and the abscissa denotes the elapse of time. Reference numeral 1700 denotes the positive voltage of the driving signal in the case of normal driving, and reference numeral 1701 denotes the positive voltage in the case of the over-voltage driving, and reference numeral 1702 denotes an optical response to the over-voltage driving, and reference numeral 1703 denotes an expected optical response in the case where the over-voltage driving is recurrently implemented. In addition, reference numeral 1704 denotes an optical response of the liquid crystal to the normal driving.
As shown in FIG. 17, due to the over-voltage driving being implemented at only one side of the AC driving (at the positive side in FIG. 17), a DC component remains; therefore, depending on the structure or the configuration of the liquid-crystal display apparatus, reliability of the liquid-crystal display apparatus may be deteriorated. Therefore, for a liquid-crystal display apparatus in which a pixel electrode and an opposite electrode are arranged on the same substrate and a voltage is generated in parallel with the substrate, a method has been proposed (refer to Japanese Patent Laid-Open No. 2001-34238) in which by, as a countermeasure, forming at least one of the pixel electrode and the opposite electrode with an ITO film, the deterioration of the reliability, due to the DC component, is prevented.
In the foregoing liquid-crystal display apparatus in which a pixel electrode and an opposite electrode are arranged on the same substrate and a voltage is generated in parallel with the substrate, by employing a structure in which at least one of the pixel electrode and the opposite electrode is formed with an ITO film, the deterioration of the reliability, due to a DC component caused by over-voltage driving, can be prevented. However, for that purpose, it is necessary to change the panel structure of a liquid-crystal display apparatus, whereby it has been a problem that the structure cannot universally be applied to various kinds of liquid-crystal display apparatuses.